System and method for operating a wireless medical device interrogation network

ABSTRACT

A system and method for operating a wireless medical device interrogation network is provided. Data exchange sessions are transacted with a wireless medical device over a plurality of interrogation points that each cover different zones of interrogation. State regarding interim data packets exchanged during each data exchange session is maintained and is accessible by each of the interrogation points. Frequency agile switching between the interrogation points and the wireless medical device during a wireless data exchange session is supported.

FIELD OF THE INVENTION

The invention relates in general to medical device interrogation and,specifically, to a system and method for operating a wireless medicaldevice interrogation network.

BACKGROUND OF THE INVENTION

Remote patient management enables clinicians to follow patient wellbeing without the presence or assistance of medical personnel. Homecarepatient management devices, such as communicators or repeaters, collectand forward patient data over a data communications network, such as theInternet, to allow patient well being to be continually monitored andcentrally analyzed.

Homecare patient management devices supplement conventional in-clinicprogrammers used to interrogate patient medical devices, which caninclude both implantable and external medical devices. Wireless personalpatient management devices allow at-home, non-clinical retrieval ofpatient data through radio frequency interrogation throughBluetooth-compliant, WiFi-compliant, WiMax-compliant, and proprietarywireless communications.

RF interrogation replaces inductive telemetry for implantable medicaldevices (IMDs) and wired connections for external medical devices(EMDs). Radio frequency-capable (RF) patient management devices,including both homecare patient management devices and advancedprogrammers for clinical and institutional use, are used to perform RFinterrogation of wireless patient medical devices. RF interrogationprovided by each such device has a finite and limited signal range,which requires patients to stay physically within range of their patientmanagement devices, particularly for implantable patient medicaldevices. The limited range can hinder interrogation sessions. In theless formal setting of a home, for instance, a patient might be temptedto move or otherwise inadvertently pass outside the range of a homecarepatient management device, thereby interrupting the data exchangesession. Moreover, some types of IMDs are designed to preserve batterylife by pulsing and modulating bidirectional transaction signal power tothe lowest level necessary to successfully transact a data exchangesession, so even minor movement can potentially affect the session.Conversely, EMDs need only be close enough to communicate with a patientmanagement device and are generally free of the RF transmissionconstraints and power management considerations of IMDs.

Other factors can further complicate interrogation sessions. RFinterrogation is also susceptible to interference from external sourcesand environmental factors, such as household appliances or physicalobstruction, which can cause a transient break or degradation intransmission signal. Moreover, homecare patient management devices arefrequently installed on a bed stand or in a bathroom, which might beinconvenient or unavailable at times when interrogation sessions arescheduled or required, such as in response to caregiver instructions.Thus, reliance on a single interrogation point can cause frustration,particularly if the patient must continually search for aninterference-free location within his or her home, or risk missing aninterrogation session.

Conventional RF patient management devices generally offer only a single“zone” of interrogation within which the patient and each patientmedical device must be physically situated during data exchangesessions. The physical constraint of a single interrogation zonerequires physical proximity and near ideal RF conditions. Furthermore,interrupted data exchange sessions must either be rescheduled, orpatient data could be lost or not timely relayed to the responsibleclinician for proper assessment and action.

U.S. Pat. No. 7,060,031, issued Jun. 13, 2006 to Webb at al. discloses amethod and apparatus for remotely programming IMDs. Caregivers generateIMD programming requests at programmers that are remotely connected to aserver. The server is securely connected to a remote monitor, whichtransmits the programming requests to the IMDs through an antennacoupled via a physical connection or wireless telemetry. A plurality ofremote monitors and antennas can be connected to the server, whichprovide multiple devices from which programming requests can betransmitted to an IMD from a single programmer. However, the Webbreference fails to disclose ensuring resilient handoff betweenphysically independent and intelligent antennas that include safeguardsagainst interference or programming session interruptions.

Therefore, there is a need for a user transparent extension to RFinterrogation range constraints for remote patient care data exchange.Preferably, such an approach would provide a plurality of interrogationpoints within a homecare or clinical setting, or other environment, andwould support automatic recovery of interrupted sessions with minimalaffect on patient actions or privacy.

SUMMARY OF THE INVENTION

A wireless medical device interrogation network is provided through apatient management device, such as a homecare communicator or repeater,or clinical advanced programmer, that is interconnected with one or moreantenna points, which together define a plurality of zones ofinterrogation. Data exchange sessions with patient medical devices areinitiated by the patient management device or programmer, whichdesignates an initial interrogation point by selecting one of theantenna points or itself. The initial interrogation point enableswandless startup, that is, the automatic initiation of an interrogationsession through long range RF, as opposed to short range inductive,telemetry. Each patient medical device is wirelessly interrogatedthrough the designated interrogation point through which patient datacan be uploaded and, in a further embodiment, programming instructionsdownloaded. The antenna points and the patient management devicemaintain state, which chronicles and tracks the progress of the dataexchange session and provides a resumption point, should the session beinterrupted or subject to interference. The antenna points and thepatient management device automatically perform a transfer of control toa new interrogation point upon sensing an interruption to seamlesslyresume the session, if, for example, the patient moves about orinterference is encountered from an external source or environmentalfactor, such as a household appliance or physical obstruction. Upon thesuccessful completion of the data exchange session, a final data set isconsolidated and provided to a centralized server or other externalsystem or data repository. Where data exchange sessions are transactedwith multiple patient medical devices, patient data and programminginstructions are respectively assembled or applied for each specificpatient and patient medical device.

One embodiment provides a system and a method for operating a wirelessmedical device interrogation network. Data exchange sessions aretransacted with a wireless medical device over a plurality ofinterrogation points that each cover different zones of interrogation.State regarding interim data packets exchanged during each data exchangesession is maintained and is accessible by each of the interrogationpoints. Frequency agile switching between the interrogation points andthe wireless medical device during a wireless data exchange session issupported. The interrogation points could each have one or moreantennas, which define or expand their respective zones ofinterrogation.

A further embodiment provides a storage medium holding computer-readablecode and a method for implementing a wireless medical deviceinterrogation protocol. A wireless data exchange session is transacted.Distinct frequency agile connections are provided with a wirelessmedical device through a plurality of interoperative interrogationpoints. Data is exchanged between the wireless medical device and theinterrogation points over the distinct frequency agile connections.Control is transferred over the wireless data exchange session. Aninterruption in the wireless data exchange session is sensed and theinterrogation point proximal to the wireless medical device isdesignated. The wireless data exchange session with the wireless medicaldevice is automatically resumed on the designated interrogation point.

A still further embodiment provides a wireless antenna point for use ina medical device interrogation network. A device interface wirelesslyconnects the wireless antenna point to a medical device. A buffer stagesdata exchanged with the medical device. State is maintained to track thedata last successfully exchanged. A network interface connect thewireless antenna point with one or more of other wireless antenna pointsand a patient management device.

Still other embodiments will become readily apparent to those skilled inthe art from the following detailed description, wherein are describedembodiments of the invention by way of illustrating the best modecontemplated for carrying out the invention. As will be realized, theinvention is capable of other and different embodiments and its severaldetails are capable of modifications in various obvious respects, allwithout departing from the spirit and the scope of the presentinvention. Accordingly, the drawings and detailed description are to beregarded as illustrative in nature and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional block diagram showing, by way of example, anautomated patient management environment.

FIG. 2 is a functional block diagram showing, by way of example, awireless medical device interrogation network organized in a one-to-onepairing.

FIG. 3 is a functional block diagram showing, by way of example, awireless medical device interrogation network organized in a one-to-manypairing.

FIG. 4 is a functional block diagram showing, by way of example, a setof wireless medical device interrogation networks organized in amany-to-one pairing.

FIG. 5 is a functional block diagram showing, by way of example, a setof wireless medical device interrogation networks organized in amany-to-many pairing.

FIG. 6 is a functional block diagram showing, by way of example, zonesof interrogation logically defined in the wireless medical deviceinterrogation network of FIG. 2.

FIG. 7 is a process flow diagram showing a method for operating awireless medical device interrogation network, in accordance with oneembodiment.

FIG. 8 is a process flow diagram showing medical device hand-off in thewireless medical device interrogation network of FIG. 2.

FIG. 9 is a timing diagram showing, by way of example, patient dataupload during a wireless medical device interrogation session.

FIG. 10 is a timing diagram showing, by way of example, programminginstruction download during a wireless medical device interrogationsession.

FIG. 11 is a process flow diagram showing data session wrap-up in thewireless medical device interrogation network of FIG. 2.

FIG. 12 is a tree diagram showing, by way of example, final data packetassembly.

FIG. 13 is a functional block diagram showing, by way of example, anantenna point for use in the wireless medical device interrogationnetwork of FIG. 2.

DETAILED DESCRIPTION

Automated Patient Management Environment

Automated patient management encompasses a range of activities,including remote patient management and automated monitoring anddiagnosis of patient health, such as described in commonly-assigned U.S.Patent application Pub. No. US2004/0103001, published May 27, 2004,pending, the disclosure of which is incorporated by reference. FIG. 1 isa functional block diagram showing, by way of example, an automatedpatient management environment 10. A patient management device 12 isinstalled in a patient's home or in a clinical or hospital environmentto provide automated patient management through wireless interrogationof patient medical devices. An advanced RF telemetry-capable programmercould also be used in a clinical or hospital environment. Additionally,other environments are possible.

Wireless interrogation of patient medical devices should only beperformed with the knowledge and permission of the patient. Thepermission can be either obtained as an implicit condition of receivingan RF-capable patient medical device, or as express permissionaffirmatively granted by the patient. Providing proper patientdisclosure and release before engaging in wireless interrogationsessions should help allay personal privacy concerns, for instance,whereabouts tracking and activities monitoring, which may present as anartifact of wireless interconnectivity.

Homecare patient management devices include repeaters and communicators,and institutional patient management devices include RF-capable advancedprogrammers that can perform wireless interrogation. The patientmanagement device 12 is remotely interconnected to a centralized server15 over an internetwork 11, such as the Internet, or through a publictelephone exchange (not shown), such as a conventional or mobiletelephone network. Other patient monitoring or communications devicesare possible. In addition, the internetwork 11 can provide bothconventional wired and wireless interconnectivity. In one embodiment,the internetwork 11 is based on the Transmission ControlProtocol/Internet Protocol (TCP/IP) network communication specification,although other types or combination of networking implementations arepossible. Similarly, other network topologies and arrangements arepossible.

Each patient management device 12 includes a user interface 13 that canbe operated by the patient, or his or her attendant, and a wirelesstransceiver 14, which provides wireless access to patient medicaldevices using wireless telemetry based on, for example, “strong”Bluetooth, IEEE 802.11 wireless fidelity “WiFi” and “WiMax,” and otherradio frequency (RF) interfacing standards. Other types andconfigurations of patient data source interfacing are possible. Patientmanagement devices 12, along with dedicated antenna points, formwireless medical device interrogation networks through which patientmedical devices are accessed, as further described below with referenceto FIGS. 2-5. Both the patient management device 12 and antenna pointsserve as an interrogation point to which a patient medical device canconnect and be interrogated. The antenna points extend the area ofphysical wireless coverage by forming interrogation zones thatsupplement the area covered by each patient management device 12. Apatient is able to move freely about during an interrogation sessionwithout risk of causing an interruption or interference, or to beinconvenienced by having only a single access point on the patientmanagement device 12.

Patient medical devices include monitoring, diagnostic, and therapeuticmedical devices, which can be implantable or external. The medicaldevices collect and forward patient data either as a primary orsupplemental function. The patient medical devices collect quantitativeobjective physiological measures on a substantially continuous orscheduled basis and also record the occurrence of events, such astherapy or irregular physiometric readings. In a further embodiment, thepatient management device 12 or other ancillary system, such as apersonal computer, records or communicates qualitative subjectivequality of life (QOL) measures that reflect the personal impression ofphysical well-being perceived by the patient at a particular time.Patient data includes physiological measures, which can be quantitativeor qualitative, parametric data regarding the status and operationalcharacteristics of the patient medical device itself, and environmentalparameters, such as the temperature or time of day. In a furtherembodiment, patient data can be directly entered by a patient. Forexample, answers to health questions can be input into the patientmanagement device 12 through the user interface 13 or through anancillary system. Other types of patient data are possible.

In a further embodiment, the collected patient data can also be accessedand analyzed by one or more clients, either locally configured systems17 a directly interfaced to the centralized server 15 orremotely-interconnected systems 17 b available over the internetwork 11.The clients systems 17 a-b can be used, for example, by clinicians tosecurely access stored patient data assembled in a database 16 coupledto the centralized server 15 and to select and prioritize patients forhealth care provisioning, such as respectively described incommonly-assigned U.S. patent application, Ser. No. 11/121,593, filedMay 3, 2005, pending, and U.S. patent application, Ser. No. 11/121,594,filed May 3, 2005, pending, the disclosures of which are incorporated byreference. Although described herein with reference to physicians orclinicians, the entire discussion applies equally to organizations,including hospitals, clinics, and laboratories, and other individuals orinterests, such as researchers, scientists, universities, andgovernmental agencies, seeking access to the patient data.

In a still further embodiment, patient medical devices can be remotelyprogrammed through the patient management device 12. The patientmanagement device 12 receives programming instructions from thecentralized server 15, which, following authentication and integritychecking, are applied to the patient medical device. Programminginstructions could also originate from the patient management device 12itself or in combination with the centralized server 15 or otherexternal sources.

In a further embodiment, patient data is safeguarded againstunauthorized disclosure to third parties, including during collection,assembly, evaluation, transmission, and storage, to protect patientprivacy and comply with recently enacted medical information privacylaws, such as the Health Insurance Portability and Accountability Act(HIPAA) and the European Privacy Directive. At a minimum, patient healthinformation that identifies a particular individual with health- andmedical-related information is treated as protectable, although othertypes of sensitive information in addition to or in lieu of specificpatient health information could also be protectable.

In a further embodiment, multiple patients and patient medical devicescan be wirelessly interrogated by commonly shared patient managementdevices 12 or advanced programmers. To ensure security and patientprivacy, patient data, and in a further embodiment, programminginstructions, include a patient medical device identifier that ensurescorrect authentication and positive patient identification.

Preferably, the server 15 is a server-grade computing platformconfigured as a uni-, multi- or distributed processing system, and theclient systems 17 a-b are general-purpose computing workstations, suchas a personal desktop or notebook computer. In addition, the patientmanagement device 12, server 15, and client systems 17 a-b areprogrammable computing devices that respectively execute softwareprograms and include components conventionally found in computingdevice, such as, for example, a central processing unit (CPU), memory,network interface, persistent storage, and various components forinterconnecting these components. Other systems and components arepossible.

Wireless Medical Device Interrogation Networks

Each patient management device 12 provides a single access point forinterfacing to patient medical devices through RF telemetry. The maximumwireless service range of a patient management device 12 is physicallylimited by the capabilities of the wireless transceiver and antennaprovided. The effective range can also be affected by external sourcesand environmental factors, such as interference from householdappliances or physical obstructions, which can both decrease thephysical range and cause “dead” spots within which poor or nonexistentsignal quality is experienced. Consequently, a patient must generallyremain within the effective communications range of the patientmanagement device throughout an interrogation session and shouldpreferably refrain from moving about to avoid causing a lapse incommunications.

The effective range of patient management devices 12 can be extended bybuilding a network of wireless access or interrogation points thatprovide wandless startup and multiple frequency agile interfaces topatient medical devices within a physical environment, such as apatient's home, medical clinic or hospital, or adult care or nursingfacility. Within the network, each patient management device 12 servesas both a centralized hub for consolidating data from all interrogationpoints and for communicating with external devices through a networkgateway or portal. In addition, the status of on-going sessions istracked through state that is accessible from all interrogation pointsto enable automatic hand-off and recovery, should a switchover betweenthe interrogation points become necessary due to, for instance, patientmovement.

One-to-One Interrogation Networks

In basic form, a single wireless medical device interrogation network 20is paired with just one patient 29, who may have one or more patientmedical devices 30-33. FIG. 2 is a functional block diagram showing, byway of example, a wireless medical device interrogation network 20organized in a one-to-one pairing. The wireless medical deviceinterrogation network 20 provides multiple wireless access orinterrogation points, which include at least one patient managementdevice 12 and one or more antenna points 21-24. Each antenna point 21provides an interrogation point that covers a different physical zonewithin the operating environment in addition to the physical zonecovered by the patient management device 12, as further described belowwith reference to FIG. 6. The multiple interrogation points allow apatient 29 to move freely about during a data exchange session withoutrisk of causing an interruption to or interference with the session, orto be limited or inconvenienced by having only the single interrogationpoint provided by the patient management device 12.

The antenna points 21-24 and the patient management device 12 eachcreate a wireless interrogation zone that may overlap or be completelydiscrete from other wireless interrogation zones in the network 20. Theinterrogation zones logically define physical areas of wireless coveragewithin which patient medical devices 21-24 can be wirelesslyinterrogated. For instance, a wireless interrogation zone could beprovided in a downstairs living room and another zone in an upstairsmaster bedroom with little to no wireless coverage in between. Wirelessinterrogation zones could also be located next to each other to providean extended wireless interrogation zone, such as might be provided in anelder care facility. Other wireless interrogation zone arrangements andtopologies are possible.

The devices 12, 21-24 collectively enable wandless startup and performfrequency agile switching to transparently transfer control between theindividual interrogation zones. Each antenna point 21-24 includes atleast one wireless transceiver and antenna 25-28 that forms a wirelessinterrogation zone, although both the patient management device 12 andthe antenna points 21-24 can have multiple wireless transceivers andantennas to further define or increase the zones of wireless coveragethat each provide.

Both the patient management device 12 and the antenna points 21-24interface to patient medical devices, which include, by way of example,medical therapy devices that deliver or provide therapy to the patient29, medical sensors that sense patient physiometry, and measurementdevices for collecting environmental and other data occurringindependent of the patient 29. Each medical device can generate one ormore types of patient data and can incorporate components for deliveringtherapy, sensing physiological data, measuring environmental parameters,or provide a combination of functionality. Medical therapy devicesinclude implantable medical devices (IMDs) 30, such as pacemakers,implantable cardiac defibrillators (ICDs), drug pumps, andneuro-stimulators, and external medical devices (EMDs) 31. Medicalsensors include implantable sensors 32, such as implantable heart andrespiratory monitors and diagnostic multi-sensor non-therapeuticdevices, and external sensors 33, 35, such as thermometers, heart ratemonitors, Holter monitors, Spirometers, weight scales 33, and bloodpressure cuffs 35. External medical devices and sensors can operateautonomously or under patient, attendant, or caregiver control, and caninclude a user interface for receiving or providing subjective patientfeedback or communications.

Generally, the patient management device 12 initiates each data exchangesession by polling one or more of the patient medical devices, asfurther described below with reference to FIG. 7. In a furtherembodiment, data exchange sessions can be scheduled to start upon theinitiative of the patient medical devices or on demand by the patient29, attendant, caregiver, or other external source. Other forms of dataexchange session initiation are possible.

During each data exchange session, the patient medical device must bewithin at least one wireless interrogation zone. The designated antennapoint 21-24 or the patient management device 12 wirelessly communicateswith the activated patient medical device through their respectivewireless transceiver 25-28 and 36. Patient data uploaded from thepatient medical devices is temporarily buffered by the interrogatingdevice and is consolidated into a final data set for the patient uponthe successful completion of the data exchange session, as furtherdescribed below with reference to FIG. 11. Generally, the patientmanagement device 12 performs the assembly and consolidation of theinterim patient data, although an antenna point 21-24 or other devicecould also perform assembly and consolidation.

During each data exchange session, the antenna points 21-24 and thepatient management device 12 monitor session progress and maintain statethat set a resumption point, should the data exchange session beinterrupted, as further described below with reference to FIG. 8. In afurther embodiment, the state is maintained by the patient medicaldevice, which tracks the data sets that have been successfully uploadedto avoid performing a duplicate upload of data already sent and toenable the patient medical device to free storage space for otherpatient data. Generally, the state includes the last packet of interimdata exchanged with the patient medical device and can include asequence number or other packet identifier. In a further embodiment, theantenna points 21-24 and the patient management device 12 can downloadprogramming instructions into the patient medical device, which can bereflected on a programming status indicator 39 or other indication on anantenna point 21-24 and the user interface 13 of the patient managementdevice 12.

The antenna points 21-24 can be interconnected to a central hub, whichis typically the patient management device 12. The antenna points 21-24can also be interconnected in series or relay. Other configurations andtopologies are possible. Additionally, the antenna points 21-24 canintercommunicate with each other and with the patient medical device 12either through wireless signals 36 or via a wired connection 37. Otherforms of medical device interrogation and network interfacing arepossible.

In a still further embodiment, the antenna points 21-24 and the patientmanagement device 12 can interface to a personal computer 34 or othergeneral purpose computing device, which can be used to collect bothquantitative and qualitative data from the patient, including QOLmeasures, such as described in commonly-assigned U.S. Pat. No. 6,221,011issued Apr. 24, 2001, the disclosure of which is incorporated byreference. Similarly, the antenna points 21-24 can include sensors 38 toprovide external monitoring of patient physiometry and other data.Finally, the patient medical device 12 can perform diagnoses andfeedback locally to a patient 29, such as described in commonly-assignedU.S. Pat. No. 6,312,378 issued Nov. 6, 2001, and U.S. Pat. No. 6,203,495issued Mar. 20, 2001, the disclosures of which are incorporated byreference. Other types of antenna point and patient medical devicefunctionality are possible.

One-to-Many Interrogation Networks

In extended form, additional interrogation networks and patient medicaldevices can be combined into expanded topologies. For example, a singlewireless medical device interrogation network can be paired withmultiple patients and their patient medical devices, such as in a homeenvironment where a single patient management device might be shared byseveral family members. FIG. 3 is a functional block diagram showing, byway of example, a wireless medical device interrogation network 40organized in a one-to-many pairing. A single patient management device41 serves as a centralized communications hub with at least one remotelycoupled antenna point 42 a-d. A plurality of patients 43-45, each ofwhom can have one or more patient medical devices, are uniquelyidentifiable by the patient management device 41, such as described incommonly-assigned U.S. patent application Ser. No. 11/301,214, filedDec. 12, 2005, pending, the disclosure of which is incorporated byreference. Each patient 43-45 is able to participate in an interrogationsession via the interrogation network 40, either individually or at thesame time, through any of the interrogation points 41, 42 a-d and thepatient management device 41 consolidates individual data packets foranalysis and forwarding to the centralized server 15, or other externalsystem or data repository. The identifier associated with each patientmanagement device is used to assemble the patient data belonging to eachpatient and patient management device, as further described below withreference to FIG. 11.

Many-to-One Interrogation Networks

Conversely, multiple wireless medical device interrogation networks canbe paired with a single patient and his or her patient medical devices,such as for a patient with a principal residence and a vacation homewith dedicated interrogation networks deployed within each. FIG. 4 is afunctional block diagram showing, by way of example, a set of wirelessmedical device interrogation networks 50 organized in a many-to-onepairing. A plurality of patient management devices 54 a-c each formdistinct interrogation networks 51, 52, 53 and serve as centralizedcommunications hubs with at least one antenna point 55 a-d, 56 a-d, 57a-d remotely coupled. A single patient 58, who can have one or morepatient medical devices, is uniquely identifiable by each patientmanagement device 54 a-c. The patient 58 is able to participate in aninterrogation session via any of the interrogation networks 51, 52, 53through any of the interrogation points 54 a-c, 55 a-d, 56 a-d, 57 a-dand each patient management device 54 a-c consolidates individual datapackets for analysis and forwarding to the centralized server 15, orother external system or data repository.

Many-to-Many Interrogation Networks

Health care environments, such as medical clinics or hospitals, andadult care or nursing facilities, frequently must be able to providecare for a population of patients throughout an environment that mayextend over a physical area significantly larger than a personalresidence. These environments are typically hostile to wireless signalexchange due to the plethora of electronic devices in operation at anytime and the reinforced construction required of commercial facilities.Providing personalized RF-enabled patient management devices tointerrogate each patient is economically infeasible and impractical, yetrelying wholly on conventional wired devices, such as inductivetelemetry programmers, severely limits patient mobility and deviceavailability.

Alternatively, a series of logically interconnected wireless medicaldevice interrogation networks can be paired with multiple patients,patient medical devices, and advanced programmers to provide an expandedinstitutional interrogation network. FIG. 5 is a functional blockdiagram showing, by way of example, a set of wireless medical deviceinterrogation networks 60 organized in a many-to-many pairing. Aplurality of patient management devices 64 a-b and advanced programmers72 each form distinct interrogation networks 61, 62, 63 and serve ascentralized communications hubs with at least one antenna point 65 a-d,66 a-d, 67 a-d remotely coupled. A plurality of patients 68-71, each ofwhom can have one or more patient medical devices, are uniquelyidentifiable by the patient management devices 64 a-b through patientmedical device identifiers. Each patient 68-71 is able to participate inan interrogation session via any of the interrogation network 61, 62,63, either individually or at the same time, through any of theinterrogation points 64 a-b, 65 a-d, 66 a-d, 67 a-d. Each patientmanagement device 64 a-b consolidates individual data packets, which arefurther consolidated by patient by either one of the patient managementdevices 64 a-b or by the centralized server 15. The patient-consolidatedpackets are then provided for analysis and forwarding to the centralizedserver 15, or other external system or data repository. The identifierassociated with each patient management device is used to assemble thepatient data belonging to each patient and patient management device, asfurther described below with reference to FIG. 11.

Zones of Interrogation

The zones of interrogation provided by the antenna points 21-24 and thepatient management device 12 collectively form the wireless medicaldevice interrogation network. FIG. 6 is a functional block diagramshowing, by way of example, zones of interrogation 80 logically definedin the wireless medical device interrogation network 20 of FIG. 2. Eachzone of interrogation 81-85 corresponds to the physical area of coverageprovided by a single wireless transceiver 25-28 and 14 respectivelyoperating on one of the antenna points 21-24 and the patient medicaldevice 12. Each interrogation zone 81-85 covers a different area, butcan overlap 36 or be entirely discrete from each other. The zones ofinterrogation 81-85 need not cover every physical part of theenvironment, such as a patient's home. Rather, the patient medicaldevice 12 and antenna points 21-24 can be strategically placedthroughout the environment to provide user friendly and convenientlocations for wireless data exchange session.

Method Overview

Data exchange sessions are performed periodically with each of thepatient medical devices to retrieve patient data that has been recordedor collected since the last interrogation and, in a further embodiment,to update programming instructions. FIG. 7 is a process flow diagramshowing a method 90 for operating a wireless medical deviceinterrogation network 20, in accordance with one embodiment. Dataexchange sessions are the primary set of operations performed during aninterrogation session between the patient medical devices and thenetwork 20, although other operations are possible, including relayinginformation to the patient 29, resetting or remotely controlling patientmedical devices, processing near real time alerts, and performingdiagnostic and trouble-shooting operations.

Each interrogation session is initiated by the patient management device12 through polling (operation 91). In a further embodiment, theinterrogation sessions can be initiated by scheduling or on demand. Thepatient management device 12 serves as the network arbiter, which isresponsible for designating the access point through which the dataexchange session will initially be performed (operation 92). The accesspoint, whether one of the antenna points 21-24 or the patient managementdevice 12, can be selected based on any combination of factors, such assignal strength, physical location, priority, assigned order, and radiofrequency. Other access point selection factors are possible.

The access point designated for interrogation conducts the interrogationof the selected patient medical device (operation 93), during whichpatient data can be received from and, in a further embodiment,programming instructions sent to the selected patient medical device.Each patient medical device is uniquely identified which, by extension,uniquely identifies the patient with whom the patient medical device isassociated. For instance, a manufacturer's serial number can be used asa patient medical device identifier, as well as a randomly assignednumber or other data. The identifier is included with each packet ofpatient data sent from and, in a further embodiment, programminginstructions received by, a patient medical device. The identifierenables correct assembly of patient data in environments in whichmultiple patients of patient medical devices could participate eithersimultaneously or while patient data from another patient or device isstill present in the network. The authenticity, integrity, and privacyof patient data can be assured by encryption and related cryptographictechniques.

A plurality of interrogation zones enables the patient 29 to move aboutfreely and provide alternate wireless communications conduits, shouldthe session be interrupted or suffer interference from an externalsource, such as a household appliance. The antenna points 21-24 and thepatient management device 12 collectively perform a hand-off to transfercontrol, as necessary, to automatically resume an interrupted dataexchange session (operation 94), as further described below withreference to FIG. 8. A hand-off is a frequency agile switch betweeninterrogation points that enables the wireless medical deviceinterrogation network 20 to provide resilience to interruptions andinterference that might otherwise cause the session to abnormallyterminate.

The interrogation session is closed upon the completion of the dataexchange session (operation 95) and the patient management device 12, orother centrally designated device, including any of the antenna points21-24, performs a wrap-up of the session (operation 96), as furtherdescribed below with reference to FIG. 11. The wrap-up consolidates thedata exchanged into a final data set, which can be forwarded to thecentralized server 15 for further processing. The network 20 thereafterreturns to a standby state pending initiation of a next interrogationsession or other activity.

Medical Device Hand-Off

Data exchange sessions occur as one-to-one communications, which pair apatient medical device to a single interrogation point, which is eithera patient management device or antenna point. One-to-many communicationsbetween a single patient medical device and multiple interrogationpoints are possible. However, contact between the patient medical deviceand the assigned interrogation point is susceptible to interruption orinterference. An on-going data exchange session can nevertheless becontinued by performing a hand-off operation. FIG. 8 is a process flowdiagram 100 showing medical device hand-off in the wireless medicaldevice interrogation network 20 of FIG. 2. A hand-off operation involvesthe patient medical device currently participating in a data exchangesession and one or more of the interrogation points, which are eitherantenna points 21-24 or the patient medical device 12. The patientmedical device 12 serves as the arbiter of the hand-off of interrogationpoint control, although any of the antenna points 21-24 could alsocontrol a hand-offhand-off. Other types of medical device hand-off arepossible.

Initially, upon sensing an interruption or interference with the dataexchange session, the patient management device 12 re-designates asubstitute interrogation point based upon the same factors considered indesignating the initial interrogation point, which include signalstrength, physical location, priority, assigned order, and frequency(operation 101). Other interrogation point selection factors arepossible. The re-designated interrogation point reacquires the wirelesssignal with the patient medical device (operation 102). Additionally,the re-designated interrogation point examines the last data blockreceived successfully from the patient medical device and other state asneeded (operation 103) to determine the point at which the data exchangesession should be resumed. The state is accessible by each of theinterrogation points and can include a sequence number assigned to eachinterim data packet received from the patient medical device. The nextdata block is thereafter re-requested from the patient medical device toresume the data exchange session and thereby complete the hand-off(operation 104).

Patient Data Upload

Data exchange sessions enable patient medical devices to upload patientdata recorded or collected since the last interrogation. FIG. 9 is atiming diagram showing, by way of example, patient data upload 110during a wireless medical device interrogation session. The x-axisrepresents time and the y-axis represents the activity level of each ofthe interrogation points 111. Interim data packets 112 represent thepatient data being uploaded.

At the outset of the data exchange session, a first antenna point AP₁ isdesignated and becomes active 113, while receiving a first set ofinterim data packets 114. Although only one interrogation point 111 isactive at any particular time throughout the data exchange session, eachremaining interrogation point continually monitors the on-going sessionand maintains state to chronicle a resumption point, should the sessionbe interrupted or suffer interference. The session is interrupted andthe patient management device PMD is re-designated as the interrogationpoint. The patient management device PMD becomes active 115 and receivesa second set of interim data packets 116, including a re-requested datapacket that was incompletely received by the first antenna point AP₁.Again, the data exchange session is interrupted. A fourth antenna pointAP₄ is re-designated as the interrogation point. The fourth antennapoint AP₄ becomes active 117 and receives a third set of interim datapackets 118. The data exchange session is again interrupted, but betweenthe transmission of successive interim data packets. A second antennapoint AP₂ is re-designated and becomes active 119 in time to receive thefourth and final set of interim data packets 120 without having tore-request patient data. The data exchange session then closes.

Programming Instruction Download

In a further embodiment, patient medical devices can be remotelyprogrammed through the wireless medical device interrogation network 20.FIG. 10 is a timing diagram showing, by way of example, programminginstruction download 130 during a wireless medical device interrogationsession. The x-axis represents time and the y-axis represents theactivity level of each of the interrogation points 131. Programmingpatches 132 represent the programming instructions being downloaded.

Unlike patient data upload, the downloading of programming instructionsmust generally occur as a logically contiguous operation to avoidleaving the patient medical device in an inconsistent state, should thedata exchange session terminate abnormally. Moreover, the programming ofClass III medical devices is regulated and requires a certified controlinfrastructure. To ensure patient safety, if programming performed aspart of a data exchange session is interrupted, such as by the patientmoving out of range, the patient is generally prompted to resume thesession, which will continue if the interruption has only been for ashort duration. If the patient either ignores the prompt or theinterruption becomes of long duration, the programming is halted and theearlier programming instructions on the patient medical device arerecovered or restored to ensure a consistent state.

Initially, a third antenna point AP₃ is designated to performprogramming instruction download and becomes active 133. However, only aportion of the programming instructions 134 are successfully downloaded,but a fourth antenna point AP₄ is re-designated and becomes active 135in time to safely resume the programming by downloading the remainingportion of the programming instructions 136.

Later, a second set of programming instructions become available and thepatient management device PMD is designated and becomes active 137. Onlya portion of the programming instructions 138 are downloaded, afterwhich the wireless medical device interrogation network 20 is unable tore-acquire a satisfactory interconnection with the patient medicaldevice being programmed. Accordingly, the patient medical deviceautomatically restores the previous set of programming instructions torecover a consistent state.

Data Session Wrap-Up

The interim patient data received by the antenna points 21-24 and thepatient management device 12 must be consolidated into a final data setupon the successful completion of each data exchange session. FIG. 11 isa process flow diagram showing data session wrap-up 140 in the wirelessmedical device interrogation network 20 of FIG. 2. In a furtherembodiment, progressive sets of patient data can be formed withoutwaiting for the completion of the entire data exchange session by onlyconsolidating the interim patient data received within preset timeintervals, or based on size, content, or other considerations. Othertypes of data session wrap-up are possible.

Each patient medical device is uniquely identified and the identifier isincluded as part of patient data and programming instructions to ensureproper authentication and positive identification of patients and theirpatient medical devices. Initially, the patient management device 12, orother centrally designated device, including any of the antenna points21-24, consolidates all of the interim data blocks that were receivedduring the data exchange session (operation 141). Any interim datablocks are assembled on a per patient and per patient medical devicebasis. For each patient and for each patient medical device, the patientmanagement device 12 evaluates the entirety of the data received(operation 142). The data is evaluated for consistency and correctness,such as by performing checksum and error detection operations.Additionally, any redundant data blocks are deleted (operation 143) anda final data set is constructed (operation 144).

In a further embodiment, the patient management device 12, or otherdesignated device, including any of the antenna points 21-24 functioningas intelligent antennas, as further described below with reference toFIG. 13, can analyze the data set (operation 145) and generate a localnotification (operation 146), for instance, advising the patient 29 topromptly contact his or her caregiver. Other post-analysis actions arepossible. Finally, the final data set is relayed to the centralizedserver 15, or other external system or data repository for furtherprocessing and analysis (operation 147).

Final Data Packet Assembly

The final data set collectively provided by the wireless medical deviceinterrogation network 20 is a superset of the interim data receivedduring the data exchange session. FIG. 12 is a tree diagram 150 showing,by way of example, final data packet assembly 151. Data blockconsolidation can be preformed hierarchically as a bottom-up data mergebased on the network topology, or by any other methodology. Thus, thepatient data 155 received by the fourth antenna point AP₄ is forwardedto the third antenna point AP₃, to which the fourth antenna point AP₄ isinterconnected in relay. The patient data 153,154 respectively receivedby the first antenna point AP₁ and the second antenna point AP₂ areforwarded to the patient management device 12, which also receivespatient data 156 forwarded from the third antenna point AP₃. The patientmanagement device PMD consolidates the received patient data 153, 154,156 with the patient data 152 that was directly received from a finaldata set 157, which is forwarded to the centralized server 15.

Antenna Point

Each antenna point 21-24 and the patient management device 12 serve asindependent but interconnected interrogation points within wirelessmedical device interrogation networks 20. The antenna points 21-24provide a cost savings by enabling the range of a patient managementdevice 12 to be flexibly extended, which can be particularly helpful inenvironments in which the full interfacing and networking features of apatient management device 12 are not required at every interrogationpoint. Additionally, the antenna points 21-24 and patient managementdevice 12 provide a network of interrogation zones formed into cells ofwireless coverage with automatic handoff and recovery.

Antenna points 21-24 and patient management devices 12 share similarcomponents for interfacing with patient medical devices. However, theantenna points 21-24 generally lack the general-purpose functionalityand patient-operable user interface 13 of patient management devices 12and need not include analysis or components for forwarding patient datato external systems or data repositories. FIG. 13 is a functional blockdiagram showing, by way of example, an antenna point 160 for use in thewireless medical device interrogation network 20 of FIG. 2. In oneembodiment, each antenna point 160 executes a sequence of program orprocess steps, such as described above beginning with reference to FIG.7, implemented, for instance, on a programmed digital computer ormicro-programmable device.

Structurally, each antenna point 160 includes one or more antennas 162a-b, processor 163, memory 164, and transceiver 165. The antennas 162a-b can provide overlapping or discrete areas of wireless coverage, orbe used in series to boost signal gain. The antenna point 160 includes apower supply 166, which can be self-contained, such as throughrechargeable batteries, or through an external power source, typicallyprovided through a standard wall outlet. Each antenna point 160 iscontained in a housing 161, which can include an indicator light 161 orother indication that confirms operation.

The processor 163 includes a controls module 167 that controls standby,interrogation session, and hand-off operations. The controls module 167conducts interrogation, during which patient data can be received fromand, in a further embodiment, programming instructions sent to aselected patient medical device. The controls module 167 also manageshand-off operations by maintaining state 173 for data exchange sessionsin a memory 164 and requesting the re-exchange of those interim datapackets, which were only partially received upon an interruption of adata exchange session. The state 173 can include a sequence number forthe last patient data block successfully received, although other typesof state are possible. Patient data packets 175 and, in a furtherembodiment, programming instructions patches 176, are transiently storedin a buffer 174 also in the memory 164. In a further embodiment, theprocessor 163 includes a manual control module 168, which enables apatient 29 or attendant to manually activate and control the antennapoint 160.

The transceiver 165 includes a wireless medical device interface 177through which to communicate with patient medical devices duringinterrogation sessions. The wireless medical device interface 177 canpulse and modulate bidirectional transaction signal power to the lowestlevel necessary to successfully transact a wireless patient dataexchange session, thereby preserving battery life on implantable patientmedical devices. In one embodiment, the interrogation sessions occurover a Bluetooth-compliant, WiFi-compliant, WiMax-compliant, orproprietary wireless data communications network. Additionally, thetransceiver 165 includes a wireless network interface 178, which enablesthe antenna point 160 to connect with other antenna points 21-24 and thepatient medical device 12. The wireless network interface 178 can alsooperate over a Bluetooth-compliant, WiFi-compliant, WiMax-compliant, orproprietary wireless data communications network. In a furtherembodiment, the transceiver 165 can include a wired network interface179, either in addition to or in lieu of the wireless network interface178, to provide a hard-wired connection to other antenna points 21-24and the patient medical device 12.

In further embodiments, the processor 163 can perform additionalfunctions to provide an “intelligent” antenna. For instance, theprocessor 163 can include an encryption module 169, which encrypts andsafeguards patient data exchanged with patient medical devices and overthe wireless medical device interrogation network 20. The encryptionmodule 169 can use, for instance, a secure key 172 based, for instance,on public key encryption or other forms of symmetric or asymmetricencryption, including the Advanced Encryption Standard (AES). Theprocessor 163 can also include a programming module 170 to downloadpatches 176 containing programming instructions to the patient medicaldevices. The processor 163 can further include a sensing module 171,which can be coupled to a sensor 180 built into or connected to theantenna point 160 to measure and record patient physiometry and otherdata. Finally, the processor 163 can include an analysis module 181,which can analyze the data set and generate a local notification. Otherantenna point functionality is possible.

While the invention has been particularly shown and described asreferenced to the embodiments thereof, those skilled in the art willunderstand that the foregoing and other changes in form and detail maybe made therein without departing from the spirit and scope of theinvention.

What is claimed is:
 1. A system for operating a wireless medical deviceinterrogation network, comprising: a plurality of interrogation pointsthat each cover different zones of interrogation to transact dataexchange sessions with a wireless medical device; a state chronicling arecord of interim data packets exchanged during each data exchangesession and accessible by each of the interrogation points, wherein thestate provides a resumption point in the event that the data exchangesession is interrupted; and at least one transceiver and one or moreantenna at each interrogation point to support frequency agile switchingbetween the interrogation points and the wireless medical device duringa wireless data exchange session.
 2. A system according to claim 1,further comprising: a controls module configured to request re-exchangewith the wireless medical device of each such interim data packetpartially received upon an interruption of the wireless data exchangesession.
 3. A system according to claim 1, further comprising: acentrally designated device configured to assemble the interim datapackets into a final data packet upon successful completion of thewireless data exchange session; and to communicate the final data packetto a server.
 4. A system according to claim 1, further comprising: awireless medical device interrogation network environment, comprising atleast one of: one such interrogation network interconnected with onepatient having at least one wireless medical device; interfacing onesuch interrogation network interconnected with a plurality of patientswho each have at least one wireless medical device; interfacing aplurality of the interrogation networks interconnected with one patienthaving at least one wireless medical device; and interfacing a pluralityof the interrogation networks interconnected with a plurality ofpatients who each have at least one wireless medical device.
 5. A systemaccording to claim 4, further comprising: a unique identifier associatedwith the wireless medical device, wherein the unique identifier isincluded with each interim data packet for use in patient and wirelessmedical device identification.
 6. A system according to claim 1, furthercomprising at least one of: a sensor configured to sense data comprisingone or more of physiological measures, parametric data, andenvironmental parameters, which is stored into interim data packets; anencryption module configured to encrypt the interim data packets duringthe wireless data exchange session; and a programming module configuredto program the wireless medical device through the wireless dataexchange session.
 7. A system according to claim 1, wherein the wirelessdata exchange session is initiated with the wireless medical devicethrough one of polling, scheduling, and on-demand.
 8. A system accordingto claim 1, wherein the interrogation points interface in at least oneof a hub configuration and a relay configuration.
 9. A system accordingto claim 1, wherein each interrogation point is selected from the groupcomprising a patient management device, advanced programmer, and antennapoint.
 10. A system according to claim 1, wherein the wireless medicaldevice is selected from the group comprising an implantable sensor,implantable therapeutic device, external sensor, and externaltherapeutic device.
 11. A method for operating a wireless medical deviceinterrogation network, comprising: transacting data exchange sessionswith a wireless medical device over a plurality of interrogation pointsthat each cover different zones of interrogation; maintaining a statechronicling interim data packets exchanged during each data exchangesession and accessible by each of the interrogation points, wherein thestate provides a resumption point in the event that the data exchangesession is interrupted; and supporting frequency agile switching betweenthe interrogation points and the wireless medical device during awireless data exchange session.
 12. A method according to claim 11,further comprising: requesting re-exchange with the wireless medicaldevice of each such interim data packet partially received upon aninterruption of the wireless data exchange session.
 13. A methodaccording to claim 11, further comprising: assembling the interim datapackets into a final data packet upon successful completion of thewireless data exchange session; and communicating the final data packetto a server.
 14. A method according to claim 11, further comprising:configuring a wireless medical device interrogation network environment,comprising at least one of: interfacing one such interrogation networkto one patient having at least one wireless medical device; interfacingone such interrogation network to a plurality of patients who each haveat least one wireless medical device; interfacing a plurality of theinterrogation networks to one patient having at least one wirelessmedical device; and interfacing a plurality of the interrogationnetworks to a plurality of patients who each have at least one wirelessmedical device.
 15. A method according to claim 14, further comprising:associating a unique identifier with the wireless medical device; andincluding the unique identifier with each interim data packet for use inpatient and wireless medical device identification.
 16. A methodaccording to claim 11, further comprising at least one of: sensing datacomprising one or more of physiological measures, parametric data, andenvironmental parameters, which is stored into interim data packets;encrypting the interim data packets during the wireless data exchangesession; and programming the wireless medical device through thewireless data exchange session.
 17. A method according to claim 11,further comprising: initiating the wireless data exchange session withthe wireless medical device through one of polling, scheduling, andon-demand.
 18. A method according to claim 11, further comprising:interfacing the interrogation points in at least one of a hubconfiguration and a relay configuration.
 19. A method according to claim11, wherein each interrogation point is selected from the groupcomprising a patient management device, advanced programmer, and antennapoint.
 20. A method according to claim 11, wherein the wireless medicaldevice is selected from the group comprising an implantable sensor,implantable therapeutic device, external sensor, and externaltherapeutic device.
 21. A wireless antenna point for use in a medicaldevice interrogation network, comprising: a device interface towirelessly connect to a medical device; a buffer to stage data exchangedwith the medical device; a state to track the data last successfullyexchanged, wherein the state comprises a sequence number for the lastpatient data block successfully retrieved; and a network interface toconnect with one or more of other wireless antenna points and a patientmanagement device; and an arbiter to designate one of the wirelessantenna points upon interruption of an active connection between medicaldevice and one such wireless antenna point.
 22. A system according toclaim 1 wherein the state further chronicles a resumption point in thedata exchange session for use if the data exchange session isinterrupted.
 23. A method according to claim 11 further comprisingre-designating an interrogation point if the data exchange session isinterrupted.
 24. A method according to claim 11 further comprisingchronicling a resumption point in the data exchange session for use ifthe data exchange session is interrupted.
 25. A system according toclaim 1, wherein the data exchanged is cardiac data and wherein thewireless medical device is an implanted medical device.